From b8672c0a1ab4521fb07073385c8989a792c59bc1 Mon Sep 17 00:00:00 2001
From: baranowb <baranowb@gmail.com>
Date: Tue, 4 Jan 2022 13:21:24 +0100
Subject: [PATCH] [UNDERTOW-2012] create temp directory for uploads

---
 .../java/io/undertow/UndertowMessages.java    |  7 ++++
 .../form/MultiPartParserDefinition.java       | 40 ++++++++++++++++++-
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/io/undertow/UndertowMessages.java b/core/src/main/java/io/undertow/UndertowMessages.java
index 6092986b01..a3e521e478 100644
--- a/core/src/main/java/io/undertow/UndertowMessages.java
+++ b/core/src/main/java/io/undertow/UndertowMessages.java
@@ -20,6 +20,7 @@
 
 import java.io.IOException;
 import java.nio.channels.ClosedChannelException;
+import java.nio.file.Path;
 
 import javax.net.ssl.SSLException;
 import javax.net.ssl.SSLHandshakeException;
@@ -636,4 +637,10 @@ public interface UndertowMessages {
 
     @Message(id = 204, value = "Out of flow control window: no WINDOW_UPDATE received from peer within %s miliseconds")
     IOException noWindowUpdate(long timeoutMiliseconds);
+
+    @Message(id = 205, value = "Path is not a directory '%s'")
+    IOException pathNotADirectory(Path path);
+
+    @Message(id = 206, value = "Path '%s' is not a directory")
+    IOException pathElementIsRegularFile(Path path);
 }
diff --git a/core/src/main/java/io/undertow/server/handlers/form/MultiPartParserDefinition.java b/core/src/main/java/io/undertow/server/handlers/form/MultiPartParserDefinition.java
index 4ed527edf1..d7738bbe67 100644
--- a/core/src/main/java/io/undertow/server/handlers/form/MultiPartParserDefinition.java
+++ b/core/src/main/java/io/undertow/server/handlers/form/MultiPartParserDefinition.java
@@ -44,12 +44,15 @@
 import java.nio.channels.FileChannel;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
+import java.nio.file.LinkOption;
 import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.nio.file.StandardOpenOption;
+import java.nio.file.attribute.FileAttribute;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.concurrent.Executor;
 
@@ -251,7 +254,42 @@ public void beginPart(final HeaderMap headers) {
                     if (fileName != null && fileSizeThreshold == 0) {
                         try {
                             if (tempFileLocation != null) {
-                                file = Files.createTempFile(tempFileLocation, "undertow", "upload");
+                                //Files impl is buggy, hence zero len
+                                final FileAttribute[] emptyFA = new FileAttribute[] {};
+                                final LinkOption[] emptyLO = new LinkOption[] {};
+                                final Path normalized = tempFileLocation.normalize();
+                                if (!Files.exists(normalized)) {
+                                    final int pathElementsCount = normalized.getNameCount();
+                                    Path tmp = normalized;
+                                    LinkedList<Path> dirsToGuard = new LinkedList<>();
+                                    for(int i=0;i<pathElementsCount;i++) {
+                                        if(Files.exists(tmp, emptyLO)) {
+                                            if(!Files.isDirectory(tmp, emptyLO)) {
+                                                //First existing element in path is a file,
+                                                //this will cause java.nio.file.FileSystemException
+                                                throw UndertowMessages.MESSAGES.pathElementIsRegularFile(tmp);
+                                            }
+                                            break;
+                                        } else {
+                                            dirsToGuard.addFirst(tmp);
+                                            tmp = tmp.getParent();
+                                        }
+                                    }
+                                    try {
+                                        Files.createDirectories(normalized, emptyFA);
+                                    } finally {
+                                        for (Path p : dirsToGuard) {
+                                            try {
+                                                p.toFile().deleteOnExit();
+                                            } catch (Exception e) {
+                                                break;
+                                            }
+                                        }
+                                    }
+                                } else if (!Files.isDirectory(normalized, emptyLO)) {
+                                    throw new IOException(UndertowMessages.MESSAGES.pathNotADirectory(normalized));
+                                }
+                                file = Files.createTempFile(normalized, "undertow", "upload");
                             } else {
                                 file = Files.createTempFile("undertow", "upload");
                             }